From apartment buildings towering over crowded urban streets to sprawling, tree-lined colonials situated on open rural roads, the most lovingly tended, pristine home can be harboring enough air-borne pollutants to get you and your family sick. You may not see it or smell it, but the Environmental Protection Agency (EPA) considers poor indoor air quality to be a top risk to public health.

Considering that many individuals spend much of their time indoors, this is not a threat to be taken lightly. Indoor pollutants can cause or contribute to asthma, lung disease, respiratory tract infections and even lung cancer. Poor indoor air quality can also cause rotting within walls and do structural damage to your dwelling. Where are the pollutants lurking in your home and what can you do about them?

Combustion Sources – Heating sources such as furnaces, heaters and water heaters, fire places, wood-burning and fuel-burning stoves can cause indoor pollution from fuel sources including gas, oil, coal and wood. The result can be higher-than-acceptable levels of carbon monoxide and nitrogen dioxide. If combustion appliances are properly installed and maintained efficiently, emissions can be greatly reduced. Furnaces should also be vented to the outdoors and woodstoves certified to meet EPA emission standards.

Furniture & Carpet – Many household furnishings such as upholstery, mattresses, drapery, carpets and pressed wood products like cabinets and dining room sets can emit formaldehyde and other chemicals specific to flame-retardation. Formaldehyde exposure can cause respiratory irritation, skin rashes and headaches and can also trigger asthma attacks. If possible, opt for formaldehyde–free furnishings such as organic mattresses or antique furniture which has already off-gassed its chemicals. If this is not an option, be sure to air out rooms in which new household items have been brought. Formaldehyde emission typically decreases over time but new items will emit higher levels of the toxin in high temperatures or humidity. If all else fails, buy a plant. Chrysanthemums and spider plants are particularly beneficial for absorption of formaldehyde and other indoor chemicals.

Tobacco – Smoking is not good for you or for your home. Second-hand smoke contains over 200 toxins, many of which are known carcinogens. Smoke lingers in air, fabric and wood for many hours after the last puff has been taken, affecting everyone in the room, including children, even after the smell has dissipated.

Radon – A leading cause of lung cancer, radon makes its way into your home through cracks in walls, drains and the foundation floor. A radioactive, naturally occurring gas, radon is responsible for over 21,000 lung cancer deaths annually. Many new homes have radon-resistant features, but all structures should be tested prior to occupancy. If necessary, install and utilize a radon reduction system, most of which are relatively inexpensive.

Biological Sources – Pet dander, pollen, mold, bacteria and particles from dust mites or cockroaches can irritate indoor allergies and asthma. Maintaining a low humidity level can help reduce mold growth. Keeping your environment clean and well-aired can help stem pollution from biologicals. What you use to clean your home, however, may actually introduce new sources of indoor pollution.

Products & Pesticides – Common household products like air fresheners, dish soap and glass cleaner can contain a plethora of unpronounceable chemicals contributing to indoor air pollution. Many of these are also indicted in everything from skin irritations to cancer and endocrine disruption. It makes sense to choose the least toxic products possible, but don’t assume the words natural or green on a product’s label means it is safe or chemical free. The Environmental Working Group’s Guide to Healthy Cleaning ranks over 400 household products by health and environmental impact. Pesticide use in the home can also add greatly to the toxic load harboring in your kitchen and bathroom. No one wants to live with creepy crawlers, but make sure you keep rooms well ventilated while you spray, or look for eco-friendly alternatives to the toxic stuff.

Corey Whelan is a freelance writer in New York. Her work can be found at Examiner.com.